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Genetics, the Key to Monarch a butterfly Migration.
Monarch butterflies migrate 2,950 miles in autumn, 5,900 miles round trip. Researchers now believe genetics plays at least some part in which insects can make this amazing journey. Scientists from the University of Chicago and several other institutions published their findings yesterday in the journal Nature.
As it turns out, not every monarch is built to make such a migration. “I like to think of it as a marathon runner versus a sprinter,” Marcus Kronforst, a University of Chicago evolutionary biologist and lead study author, told The New York Times. “The migratory ones are really marathon runners.”
The researchers sequenced more than 100 genomes from around the world. They determined that a single gene factors into migration. “Migration is regarded as a complex behavior, but every time that the butterflies have lost migration, they change in exactly the same way, in this one gene involved in flight muscle efficiency,” Kronforst said in a news release. “In populations that have lost migration, efficiency goes down, suggesting there is a benefit to flying fast and hard when they don’t need to migrate.”
Kronforst and his colleagues also learned that another single gene — a different one — determines pigmentation. By comparing the genes of a small black-and-white population of monarchs in Hawaii with populations with normal coloration, the team found what they describe as a “pigmentation switch.”
These butterflies, probably the most familiar of their kind, are the only ones known to make such a two-way trip, according to the U.S. Forest Service. They fly up to 100 miles a day, taking as long as two months for the entire journey. The site at the roost is one of wonder, with throngs of butterflies hanging off the forest trees like orange-and-black leaves.
Though monarchs as a whole aren’t in trouble, earlier this year, the Mexican government and the World Wildlife Fund reported a smaller migrating population than ever before, around 35 million individuals. The forest where they spend the winter also shrunk to less than half the size it was the previous year, The New York Times noted.
The results of this study, the authors say, highlight the need for conservation action. “You used to see huge numbers of monarchs, clouds of them passing by,” Kronforst said. “Now it looks quite possible that in the not too distant future, this annual migration won’t happen.”
As it turns out, not every monarch is built to make such a migration. “I like to think of it as a marathon runner versus a sprinter,” Marcus Kronforst, a University of Chicago evolutionary biologist and lead study author, told The New York Times. “The migratory ones are really marathon runners.”
The researchers sequenced more than 100 genomes from around the world. They determined that a single gene factors into migration. “Migration is regarded as a complex behavior, but every time that the butterflies have lost migration, they change in exactly the same way, in this one gene involved in flight muscle efficiency,” Kronforst said in a news release. “In populations that have lost migration, efficiency goes down, suggesting there is a benefit to flying fast and hard when they don’t need to migrate.”
Kronforst and his colleagues also learned that another single gene — a different one — determines pigmentation. By comparing the genes of a small black-and-white population of monarchs in Hawaii with populations with normal coloration, the team found what they describe as a “pigmentation switch.”
These butterflies, probably the most familiar of their kind, are the only ones known to make such a two-way trip, according to the U.S. Forest Service. They fly up to 100 miles a day, taking as long as two months for the entire journey. The site at the roost is one of wonder, with throngs of butterflies hanging off the forest trees like orange-and-black leaves.
Though monarchs as a whole aren’t in trouble, earlier this year, the Mexican government and the World Wildlife Fund reported a smaller migrating population than ever before, around 35 million individuals. The forest where they spend the winter also shrunk to less than half the size it was the previous year, The New York Times noted.
The results of this study, the authors say, highlight the need for conservation action. “You used to see huge numbers of monarchs, clouds of them passing by,” Kronforst said. “Now it looks quite possible that in the not too distant future, this annual migration won’t happen.”
